Interpreter cleanup

[Frederic Parain]

Here’s a patch with a set of simplifications of the interpreter support
for vbytecodes.

http://cr.openjdk.java.net/~fparain/interpreter_cleanup/webrev.00/

Sergey has identified method find_field_from_offset() as a performance
issue. Unfortunately, it was used a lot in the interpreterRuntime code.

The changeset gets rid of all calls to this method in the interpreter runtime.

The changes also make a better usage of values computed by the
assembly code of the template interpreter, passing these values to
the runtime rather than letting the interpreter runtime computing them again.

The changes pass hotspot_valhalla and idk_valhalla_mvt test suites.

Fred